Observational confirmation of the Sun's CNO cycle

Gamma rays from a solar flare in Active Region 10039 on 23 July 2002 with the RHESSI spacecraft spectrometer indicate that the CNO cycle occurs at the solar surface, in electrical discharges along closed magnetic loops. At the two feet of the loop, H ions are accelerated to energy levels that surpass Coulomb barriers for the C-12[H-1, gamma]N-13 and N-14[H-1, gamma]O-15 reactions. First x-rays appear along the discharge path. Next annihilation of positrons from N-13 and O-15 [half-life = 10 m and 2 m] produce bright spots of 0.511 MeV gammas at the loop feet. As C-13 increases from positron decay of N-13, the C-13[He-4, n]O-16 reaction produces neutrons and then the 2.2 MeV emission line appears from n-capture on H-1. These results suggest that the CNO cycle changed the N-15/N-14 ratio in the solar wind and at the solar surface over geologic time, and this ratio may contain an important historical record of climate changes related to sunspot activity.Comment: 9 pages, 21 references, 2 figures show x-rays and gamma-rays from nuclear reactions in a solar-flare-induced electrical discharge. Replaced to show publication detail

On the Cosmic Nuclear Cycle and the Similarity of Nuclei and Stars

Repulsive interactions between neutrons in compact stellar cores cause luminosity and a steady outflow of hydrogen from stellar surfaces. Neutron repulsion in more massive compact objects made by gravitational collapse produces violent, energetic, cosmological events (quasars, gamma ray bursts, and active galactic centers) that had been attributed to black holes before neutron repulsion was recognized. Rather than evolving in one direction by fusion, nuclear matter on the cosmological scale cycles between fusion, gravitational collapse, and dissociation (including neutron-emission). This cycle involves neither the production of matter in an initial Big Bang nor the disappearance of matter into black holes. The similarity Bohr noted between atomic and planetary structures extends to a similarity between nuclear and stellar structures.Comment: 21 pages, 4 figure

How Social Enterprises Coordinate Cross-Sectoral Solutions for Informal Settlements: A Case Study of Terra Nova in Brazil

HonorsInternational StudiesUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/169405/1/mozinam.pd

How does predicate invention affect human comprehensibility?

During the 1980s Michie defined Machine Learning in terms of two orthogonal axes of performance: predictive accuracy and comprehensibility of generated hypotheses. Since predictive accuracy was readily measurable and comprehensibility not so, later definitions in the 1990s, such as that of Mitchell, tended to use a one-dimensional approach to Machine Learning based solely on predictive accuracy, ultimately favouring statistical over symbolic Machine Learning approaches. In this paper we provide a definition of comprehensibility of hypotheses which can be estimated using human participant trials. We present the results of experiments testing human comprehensibility of logic programs learned with and without predicate invention. Results indicate that comprehensibility is affected not only by the complexity of the presented program but also by the existence of anonymous predicate symbols

Stability of Diethyl Carbonate in the Presence of Acidic and Basic Solvents

Reducing carbon dioxide (CO2) emissions is an inevitable measure for fighting anthropogenic climate change. Carbon Capture and Utilization (CCU) technologies are gaining rising attention as an additional contributor to reaching the Paris Agreement goals. Giving CO2 a value as a feedstock to be refined into chemicals to be used in industry is a crucial aspect of making these technologies interesting for vast industrial sectors. The synthesis of diethyl carbonate (DEC) is recognized as a promising prospect for the successful implementation of CCU. DEC is considered a fully biodegradable, low-toxic solvent, which can be synthesized from CO2 and ethanol in the presence of a catalyst. DEC may be a non-toxic alternative to other solvents such as toluene or methyl isobutyl ketone (MIBK). The optimization of DEC synthesis is one aspect that is under investigation today. For the exploration of DEC's applicability, an extensive amount of data is beneficial. Many applications of solvents involve the presence of acids and bases. Hence, an interest in DEC in various environments is reasonable. The decomposition of DEC after contact with water, different acids and bases at room temperature, and the boiling point was determined experimentally to characterize chemical stability. Further, the influence of sodium chloride and a cerium-based catalyst used in DEC synthesis was investigated